This is a commentary on gender identity, beginning with what historically has been the dominant gender and how with each new definition that people have been comfortable in affording themselves, the conversation grows.
Even though those conversations can seem muddled, busy or confusing to outsiders yet to understand, empathise - or even choose to do neither - there's still growth that comes from those conversations below the surface as long as those conversations continue - as shown by the progression of the plant and the new seedlings inspired in the last panel.
Respect the identity and pronouns of others. It's simple.